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NITED STATES CHARLES F. GROSELMIRE, OF NEYVARK, NEV JERSEY.

WET PROCESS OF EXTRACTING PURE ZINC FROM ITS ORES.

SPECIFICATION forming part of Letters Patent N0.379,764, dated March 20, 1888.

Application filed April 27, 1887. Serial No. 236,346.

To aZZ whom it may concern.-

Be it known that I, Cannons F. ORosEL- MIRE, a citizen of the United States, residing at Newark, in the county of Essex and State of New Jersey, have invented a new and use ful \Vet Process of Extracting Pure Zinc from Zinciferous Ores, of which the following specification is a full, clear, and exact description.

My invention consists in the process of extracting pure zinc by roasting the pulverized ziucifcrous ore, and then subjecting the same to an aerated acid bath, and finally depositing or precipitating the zinc, substantially as I will now proceed to particularly set forth and claim.

It is well known that great loss has occurred in separating zinc from zinciferous ores and the zinc obtained was impure, and where the ore contained the precious metals, and especially silver, much of thelatter has been driven off in vapor with the zinc in the operation of smelting. In addition, where there is a considerable percentage of zinc with the silver, it is impossible to carry 011 the smelting operation.

An effort has been made to get rid of the zinc in galenas carrying silver and metallic sulphides and oxides, but with only partial success, and the zinc obtained was impure, and when the ore contained iron and manganese the zinc was largely impregnated therewith. The zinc obtained by this last mentioned method is practically valueless as an article of commerce, while the zinc obtained as the result of my method is chemically pure.

Incarrying outmy process Ifirst pulverizethe ore and then feed it dry into a furnace, preferably a reverl'ieratory one, and roast it, using either an air-blast or ajet of steam during the operation of roasting. The heat is regulated so that a considerable percentage of the sulphide of zinc in the ore is converted into a sulphate. I next remove the roasted ore from the furnace into a tank containing a dilute solution of sulphuric acid, which has the eii'cct of holding the zinc in suspension While the other metals are precipitated, unless the ore contains iron and manganese, the effect on which by theacid will be hereinafter explained. The acid solutionnsed is one of definite pro (No specimens.)

portions, and consists of one equivalent of the acid for each equivalent of zinc contained in the ore, which can be determined by analysis. I have found by experiment that this is essential if chemically pure zinc is to be obtained. In other words, if the ore should contain sixteen parts of zinc the acid solution should be in the same proportion, or one part of acid to sixteen parts of water.

The zinc in solution produced by the use of sulphuric acid will of course be a sulphate.

If it should be desired to obtain the chloride of zinc instead, I substitute hydrochloric acid for sulphuric in the same proportions. ore contains iron and manganese, it will be apparent that these two metals will also be attacked by and largely held in solution by the action of the dilute acid. To get rid of these metals, I introduce a blast into or through the tank containing the acid and ores, and the result is that I throw down the iron and manganese by thus forming peroxide thereof, leaving the zinc alone in suspension. I then draw ott" this solution,and the zinc may be deposited directly therefrom by the use of a dynamoelectrical machine; or it may be precipitated as a carbonate or oxide by any of the known methods. 1

The precipitated pulp remaining in the tank after zinc solution is drawn ofi' may be washed, molded into bricks, and smelted; or the different metals may be separated by any ofthe usual and customary processes.

I use either a hot or a cold blastin the tank to precipitate the iron and manganese as peroxide, and while I prefer to use superheated steam, I do not limit myself to the use of such means.

It will be seen that the solution used is so weak that it does not attack the silver or lead in the ore, and only to a limited degree the iron and manganese, and that the two lastnamcd metals are wholly precipitated as peroxides by the blast, as already stated.

I prefer to use the blast,as already described, through or over the orein the operation ot'roasting, and generally do so in practice.

It is not absolutely essential that it be always used, and might sometimes be dispensed with; but in this event a stronger,and therefore more If the expensive,acid solution would be necessary, as there would be no sulphates of the zinc, which would be readily soluble in a weak acid.

The value and importance of my improvement will be readily apparent.

I am enabled to produce from zinciferous ores a chemically-pure zinc--a resulthitherto practicall y unattainable-and that too at a com paratively insignificant cost. \Vhere such ores contain silver, by my process I leave the latter entirely free from zinc alloy.

Having thus fully described my improvement, What I claim as my invention, and desire to secure by Letters Patent. is

1. That improvement in the art of obtaining pure zinc from zinciferous ores, which consists in pulverizing the ore, roasting the pulverized ore in a suitable furnace, and passing a blast through or over it, next immersing the roasted ore indilute acid, passing a blast through the solution until the impurities are oxidized, and finally drawing offthe zinc solution and depositing or precipitating the zinc, substantially as set forth. 2. The process which consists in immersing roasted zinc ore in dilute acid, passing an air blast through the solution until the impurities are oxidized. and finally drawing'off the zinc solution and depositing or precipitating the zinc, substantially as set forth.

In testimony whereof I affix my signature in presence of two witnesses.

CHARLES F. OROSELMIRE. Witnesses:

J os.' D. FRANZONA, JOHN A. DRAWBAUGH. 

